Slattery told Shortlist: "I don't think she is misunderstood by anyone else but that one kid. Coincidentally, that kid doesn't play Bobby Draper anymore. Not because of what he said...They've had about five Bobby Drapers and they can't seem to find one who doesn't look straight into the lens.

"I think the problem is that January is an incredible actress. She plays a formidable character, she's not mother of the year, she has a hard relationship with that child and she's horrible to him. It's remarkable to watch her, actually.

"That poor f**king kid, I'm not surprised she scared the hell out of him. She'd scare the hell out of me."

Slattery also revealed that fans should not expect Roger's rough times to come to an end in season five.

"You know, it's funny, there is a line where Roger talks about happiness and how fleeting it is," he said. "I think that's what it is all about with these characters on Mad Men.

"They're all just looking for happiness. They want something and they get it - and then they're disappointed. That's the show in a nutshell right there."

Mad Men airs Sunday (March 25) from 9pm on AMC, and will land in the UK two days later on Sky Atlantic.